Possible - Yes. Large enough will certainly work. Any aluminum mast
just strong enough will also bend in the wind a surprising amount.
Another problem will be the joint right at 20' since that is the length
of standard aluminum pipe/tube and the point of highest stress in the
20' unsupported section. The splice will need some careful thought and
implementation.
Then you don't specify the wind conditions, so without them there is no
calculation.
A mast calculator
http://thebont.com/spreadsheets/AnalysisOfAntennaMastStrength.htm
I suggest you start with analyzing 2.5" IPS schedule 40 6061-T6 aluminum
pipe, and go smaller or bigger depending on the results.
The house will probably need reinforced at the bearing and the mount
plenty beefy and be able to spread the load.
A better alternative would be 30 ft of Rohn 25, a house bracket and 5'
of exposed steel mast to an internal rotator, if you are willing to
climb a bit.
Grant KZ1W
On 12/11/2017 18:23 PM, Terry Brown wrote:
I want to put a Mosley TA 33 Jr. that weighs 21 lbs. on a 36 ft. tubular mast.
My rotor will be at the bottom of the mast. I will put a bearing that attaches
to my house by a bracket at 16 ft.
Will it be possible to get some size of aluminum tubing to use that can stick
up 20 ft. unsupported that will hold the antenna?
Thanks,
Terry, N7TB
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